scholarly journals Volume-timing relationships during cough and resistive loading in the cat

2000 ◽  
Vol 89 (2) ◽  
pp. 785-790 ◽  
Author(s):  
Donald C. Bolser ◽  
Paul W. Davenport
Keyword(s):  
Linear Relationship ◽  
Negative Slope ◽  
Inspiratory Time ◽  
Positive Slope ◽  
Single Breath ◽  
Resistive Loading ◽  
Resistive Loads ◽  
The Relationship ◽  
Pattern Regulation ◽  
Pulmonary Volume

The relationship between pulmonary volume-related feedback and inspiratory (CTi) and expiratory (CTe) phase durations during cough was determined. Cough was produced in anesthetized cats by mechanical stimulation of the intrathoracic tracheal lumen. During eupnea, the animals were exposed to single-breath inspiratory and expiratory resistive loads. Cough was associated with large increases in inspiratory volume (Vi) and expiratory volume (Ve) but no change in phase durations compared with eupnea. There was no relationship between Viand CTi during coughing. A linear relationship with a negative slope existed between Vi and eupneic inspiratory time during control and inspiratory resistive loading trials. There was no relationship between Ve and CTe during all coughs. However, when the first cough in a series or a single cough was analyzed, the Ve/CTe relationship had a positive slope. A linear relationship with a negative slope existed between Ve and eupneic expiratory time during control and expiratory resistive loading trials. These results support separate ventilatory pattern regulation during cough that does not include modulation of phase durations by pulmonary volume-related feedback.

Relationship between resistive loads and P1 peak of respiratory-related evoked potential

1997 ◽  
Vol 83 (3) ◽  
pp. 918-926 ◽  
Author(s):  
Marie Knafelc ◽  
Paul W. Davenport
Keyword(s):  
Linear Relationship ◽  
Magnitude Estimation ◽  
Evoked Potential ◽  
Neural Activation ◽  
Resistive Load ◽  
Physical Magnitude ◽  
Series Of Experiments ◽  
Positive Peak ◽  
Resistive Loads ◽  
The Relationship

Knafelc, Marie, and Paul W. Davenport. Relationship between resistive loads and P1peak of respiratory-related evoked potential. J. Appl. Physiol. 83(3): 918–926, 1997.—This study investigated the relationship between resistive-load (ΔR) magnitude, the first positive peak (P1) amplitude of the respiratory-related evoked potential (RREP), and load-magnitude estimation (ME). The first experiments determined the subject’s ( n = 9) ME of five ΔR magnitudes randomly presented at the onset of an inspiration or by interrupting an inspiration. No significant differences were found in the slopes of the two different presentations, but the subjects estimated the interrupted inspiratory loads to be of lesser magnitude than loads presented at the onset of the breath. In the second series of experiments, the subject’s ( n = 6) RREPs were recorded in response to three ΔR magnitudes. The amplitude of the short-latency P1 peak of the RREP significantly increased with increases in the ΔR magnitude. A log-log plot of the group-averaged P1 amplitudes showed a linear relationship with ΔR. These results were consistent with the hypothesis that the perceptual magnitude of the respiratory load was related to the P1 amplitude of the RREP, suggesting the physical magnitude of the load-related stimulus was correlated with the amplitude of the cortical neural activation.

Effect of expiratory loading on expiratory duration and pulmonary stretch receptor discharge

1986 ◽  
Vol 61 (5) ◽  
pp. 1857-1863 ◽  
Author(s):  
P. W. Davenport ◽  
J. A. Wozniak
Keyword(s):  
Linear Relationship ◽  
Temporal Summation ◽  
Spatial Summation ◽  
Stretch Receptor ◽  
Single Breath ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Temporal And Spatial ◽  
Resistive Loads ◽  
Pulmonary Stretch Receptor

Slowly adapting pulmonary stretch receptors have been hypothesized to be the afferents mediating the vagally dependent, volume-related prolongation of expiratory time (TE) during expiratory loading. It has been further suggested that the vagal component of this prolongation of TE is due to the temporal summation of pulmonary stretch receptor (PSR) activity during expiratory loading. This hypothesis was tested in rabbits exposed to resistive and elastic single-breath expiratory loading while PSR′s were simultaneously recorded. Both types of loads resulted in a decreased expired volume (VE) and increased expiratory duration (TE). The TE for resistive loads were significantly greater than for elastic loads for equivalent VE. Thus two different VE-TE relationships were found for resistive and elastic loads. When TE was plotted against the area under the expired volume trajectory, a single linear relationship was observed. PSR activity recorded during expiratory loading increased as VE decreased and TE increased. A single linear relationship resulted when the number of PSR spikes during the expiration was plotted against the associated TE for all types of loads. These findings demonstrate that the volume-related prolongation of TE with single-breath expiratory loads is associated with an increase in PSR discharge. These results support the hypothesis that the vagal component of load-dependent prolongation of TE is a function of both the temporal and spatial summation of PSR activity during the expiratory phase.

Response of ventral respiratory group inspiratory neurons to mechanical loading

1983 ◽  
Vol 54 (1) ◽  
pp. 254-261 ◽  
Author(s):  
R. G. Seaman ◽  
F. W. Zechman ◽  
D. T. Frazier
Keyword(s):  
Neural Responses ◽  
Inspiratory Time ◽  
Mechanical Loads ◽  
Ventral Respiratory Group ◽  
Elastic Load ◽  
Inspiratory Neurons ◽  
Resistive Loading ◽  
Cervical Vagotomy ◽  
Resistive Loads ◽  
Predominant Effect

The bursting patterns of 32 ventral respiratory group (VRG) medullary inspiratory neurons were studied in response to selected mechanical loads in 68 allobarbital-urethan-anesthetized cats. Mechanical loads consisted of three levels of resistive loads, one elastic load, and tracheal occlusion (TO). The application of each load was manipulated to oppose either inspiration or expiration. Loads were applied for only one inspiration or expiration to prevent changes in chemical drive. All loaded breath unit responses were analyzed and compared with control values for inspiratory time (TI), expiratory time (TE), spikes per burst (SPB), and average firing rate (FR). Inspiratory mechanical loads resulted in statistically significant increases in TI and SPB but only small nonsignificant increases in FR and TE. Expiratory resistive loading produced its predominant effect on TE. The higher expiratory mechanical loads also caused significant increases in the subsequent unloaded TI and SPB. In contrast to expiratory loading, large inspiratory loads did not significantly affect the next unloaded TE. Bilateral cervical vagotomy eliminated the observed neural responses to loading for both inspiratory and expiratory loads. All of the 71 neurons tested with lung inflations and TO at end inspiration showed inhibition (Ra type) rather than facilitation (R beta).

Characteristics of inspiratory inhibition by phasic volume feedback in cats

1978 ◽  
Vol 45 (1) ◽  
pp. 80-86 ◽  
Author(s):  
M. K. Younes ◽  
J. E. Remmers ◽  
J. Baker
Keyword(s):  
Lung Volume ◽  
Time Dependent ◽  
Inspiratory Time ◽  
Reversible Inhibition ◽  
Single Breath ◽  
Inspiratory Phase ◽  
Inspiratory Activity ◽  
The Relationship ◽  
Obvious Relation ◽  
Volume Range

The dependence of phrenic efferent discharge on vagal-volume feedback was examined in barbiturate-anesthetized, paralyzed cats ventilated by a phrenic-driven servo respirator. The characteristics of the respiratory were altered for a single breath, and the resulting change in phrenic activity was quantitated by comparison with phrenic activity without phasic volume feedback. The relation between volume feedback and phrenic inhibition was determined both when inspiratory termination occurred during the rising phase of phrenic discharge and during the plateau observed with barbiturate-induced apneusis. Inhibition of inspiratory activity occurred only when lung volume exceeded a time-dependent threshold. Above this threshold, andextending over a substantial volume range, volume feedback caused graded and reversible inhibition of phrenic discharge. The threshold for graded inhibition declined progressively during the inspiratory phase, showing no obvious relation to the level of inspiratory activity. At any particular time, the relation between volume and phrenic inhibition was convex to the volume axis, and the slope of the relationship increased with inspiratory time. The results indicate that a) volume feedback inhibits inspiration in a graded manner, b) partial inhibition of phrenic activity renders it more susceptible to additional inhibition, and c) inhibitory effectiveness of volume feedback increases with time.

Control of inspiratory duration in premature infants

1988 ◽  
Vol 64 (6) ◽  
pp. 2597-2604 ◽  
Author(s):  
R. E. Fox ◽  
P. C. Kosch ◽  
H. A. Feldman ◽  
A. R. Stark
Keyword(s):  
Premature Infants ◽  
Term Infants ◽  
Single Breath ◽  
Elastic Load ◽  
Resistive Loading ◽  
Elastic Loading ◽  
Measured Flow ◽  
Respiratory Valve ◽  
Reflex Control ◽  
Resistive Loads

We used single-breath mechanical loads and airway occlusions in premature infants to determine whether maturation influences the reflex control of inspiratory duration. We measured flow, volume, airway pressure, and surface diaphragmatic electromyogram (EMG) in 10 healthy preterm infants [33 +/- 1 (SD) wk gestation], 2–7 days of age. Three resistive and two elastic loads and occlusions were applied to the inspiratory outlet of a two-way respiratory valve. Application of all loads resulted in inspired volumes significantly decreased from control (P less than 0.001), and these decreases were progressive with increasing loads. Inspiratory duration (TI) was prolonged from control by all loads and occlusions when measured from the diaphragmatic EMG (neural TI) and by all but the smaller elastic load when measured from the flow tracing (mechanical TI). Similar decreases in inspired volume at the end of neural TI produced by application of both elastic and resistive loads resulted in comparable prolongation of neural TI. In contrast, for comparable volume decrements, resistive loading prolonged mechanical TI more than elastic loading (P less than 0.001). Mechanical and neural TI values of the breath after the loaded breath were unchanged from control values. Comparison of the neural volume-timing relationship in premature infants with our data in full-term infants suggests that the strength of the timing response to similar relative decrements in inspired volume is comparable. We conclude that reflex control of neural TI in premature infants depends on the magnitude of inspired volume and is independent of the volume trajectory.

Ventilatory responses to inspiratory flow-resistive loads in awake and sleeping dogs

1983 ◽  
Vol 54 (6) ◽  
pp. 1550-1557 ◽  
Author(s):  
G. Bowes ◽  
L. F. Kozar ◽  
S. M. Andrey ◽  
E. A. Phillipson
Keyword(s):  
Ventilatory Response ◽  
Nrem Sleep ◽  
Lateral Position ◽  
Inspiratory Flow ◽  
Quiet Wakefulness ◽  
Ventilatory Responses ◽  
Single Breath ◽  
Resistive Loading ◽  
Resistive Loads ◽  
Ventilatory Response To Co2

We studied ventilatory responses to inspiratory flow-resistive loads in six trained dogs, during quiet wakefulness and non-rapid-eye-movement (NREM) sleep. During studies dogs lay quietly in a lateral position and breathed through an endotracheal tube inserted via a chronic tracheostomy. Linear resistances of 6, 10, 19, and 31 cmH2O X l-1 X s were applied during inspiration for only a single breath to assess the immediate ventilatory response. The highest resistance was also applied for five successive breaths to assess the progressive ventilatory response. Ventilatory responses to hyperoxic progressive hypercapnia were also examined, with and without flow-resistive loading. During loading the maintenance of constant states of quiet wakefulness and NREM sleep was confirmed by electroencephalographic monitoring. Ventilation decreased on the first loaded breath and returned to control in a stepwise manner by the fifth loaded breath. No state-related differences were observed in either the immediate or progressive ventilatory responses. During CO2 rebreathing, the slope of the ventilatory response to CO2 was reduced by loading, with the reduction in slope (as percent of control) greater in the NREM state. We therefore conclude that in the dog immediate and progressive ventilatory responses to resistive loads are unaffected by NREM sleep, whereas the decrease in ventilatory response to CO2 resulting from loading tends to be greater in NREM sleep than in quiet wakefulness.

The Structural Stability of the Concentration-Performance Relationship in Food Manufacturing

1982 ◽  
Vol 14 (2) ◽  
pp. 43-49
Author(s):  
Stephen E. Miller
Keyword(s):  
Industrial Organization ◽  
Linear Relationship ◽  
Structural Stability ◽  
Market Performance ◽  
Continuous Linear ◽  
Food Manufacturing ◽  
The Relationship

The literature of industrial organization is replete with analyses of the relationship between seller concentration and market performance. Most researchers have hypothesized a continuous linear relationship between profitability and concentration and have estimated that relationship accordingly.

Measuring Strains for Hematite Phase in Sinter Ore by Electron Backscattering Diffraction Method

2006 ◽  
Vol 326-328 ◽  
pp. 237-240 ◽  
Author(s):  
Yasushi Sasaki ◽  
Manabu Iguchi ◽  
Mitsutaka Hino
Keyword(s):  
Linear Relationship ◽  
Strain Gauge ◽  
Diffraction Method ◽  
Local Strain ◽  
Electron Backscattering ◽  
Hematite Phase ◽  
Compression Strain ◽  
Electron Backscattering Diffraction ◽  
Ebsd Technique ◽  
The Relationship

Based on the relationship between quantified blurring degree of Kikuchi bands obtained by an electron backscattering diffraction (EBSD) technique and macroscopic strains measured by a strain gauge, the local compression strain SEBSD in sinter ore has been evaluated under various conditions. There is a good linear relationship between the SEBSD and the strains measured by a strain gauge. The local strain SEBSD evaluated by EBSD patterns can be used as an index of local strains.

LA MESURE DE L’INTERFÉRENCE DU CHIENDENT DANS L’ORGE

1982 ◽  
Vol 62 (1) ◽  
pp. 183-188 ◽  
Author(s):  
R. RIOUX
Keyword(s):  
Regression Analysis ◽  
Hordeum Vulgare ◽  
Linear Relationship ◽  
Linear Relation ◽  
Shoot Density ◽  
Yield Variability ◽  
Hordeum Vulgare L ◽  
The Mean ◽  
The Relationship ◽  
Agropyron Repens

Barley (Hordeum vulgare L. ’Champlain’) was grown with quackgrass (Agropyron repens (L.) Beauv.) at various densities for 3 yr. According to the regression analysis, a linear relation is appropriate to describe the relationship between yield of barley and biomass or density of quackgrass. A greater proportion of yield variability was explained by density (64%) than by biomass (40%). Density is then a better criterion than biomass to predict yield lost in barley. The linear relationship between barley yield and the shoot density of quackgrass is estimated by the following equation: yield barley = 345.3–0.5682 dens, quackgrass. An increase of 10 shoots/m2 in the mean density of quackgrass resulted in a mean loss of 6 g/m2 in the yield of barley.

scholarly journals Methods of Controlling Lift - off in Conductivity Invariance Phenomenon for Eddy Current Testing

2020 ◽  
Author(s):  
Zhongwen Jin ◽  
Yuwei Meng ◽  
Rongdong Yu ◽  
Ruochen Huang ◽  
Mingyang Lu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Eddy Current ◽  
Coating Thickness ◽  
Test Sample ◽  
Common Point ◽  
Coil Design ◽  
Current Testing ◽  
Lift Off ◽  
Two Parameters ◽  
The Relationship

<p>Previously, a conductivity invariance phenomena (CIP) has been discovered – at a certain lift-off, the inductance change of the sensor due to a test sample is immune to conductivity variations, i.e. the inductance – lift-off curve passes through a common point at a certain lift-off, termed as conductivity invariance lift-off. However, this conductivity invariance lift-off is fixed for a particular sensor setup, which is not convenient for various sample conditions. In this paper, we propose using two parameters in the coil design – the horizontal and vertical distances between the transmitter and the receiver to control the conductivity invariance lift-off. The relationship between these two parameters and the conductivity invariance lift-off is investigated by simulation and experiments and it has been found that there is an approximate linear relationship between these two parameters and the conductivity invariance lift-off. This is useful for applications where the measurements have restrictions on lift-off, e.g. uneven coating thickness which limits the range of the lift-off of probe during the measurements. Therefore, based on this relationship, it can be easier to adjust the configuration of the probe for a better inspection of the test samples.</p>

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